biology-cell divison

Meiosis I

The first round of meiotic cell division that separates homologous chromosomes, reducing ploidy from diploid ($2n$) to haploid ($n$).

Synapsis

The side-by-side pairing of homologous chromosomes during Prophase I to form tetrads.

Crossing over

The exchange of genetic material between non-sister chromatids of homologous chromosomes at chiasmata during Prophase I.

Tetrad

A structure consisting of four chromatids formed by a paired set of homologous chromosomes during Prophase I.

Metaphase I

The stage of division where paired homologous chromosomes align randomly along the cell equatorial plate.

Anaphase I

The stage of division where homologous chromosomes pull apart to opposite poles while sister chromatids remain joined at centromeres.

Telophase I

The stage of division where nuclear envelopes reform around two distinct haploid ($n$) chromosome clusters prior to cytokinesis.

Independent assortment

The random orientation of maternal and paternal homologous chromosome pairs along the equator during Metaphase I, creating genetic variability.